This application claims the benefit of Korean Application No. 2002-80188, filed Dec. 16, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates, in general, to wall-mounted type microwave ovens and, more particularly, to a wall-mounted type microwave oven which is designed to allow a power cord to be easily and efficiently mounted to the microwave oven.
2. Description of the Related Art
As is well known to those skilled in the art, a wall-mounted type microwave oven is installed above an oven range, in a kitchen. The wall-mounted type microwave oven serves to exhaust gas or smoke produced from the oven range which is positioned under the microwave oven, in addition to cooking food by microwaves in the wall-mounted type microwave oven.
The wall-mounted type microwave oven includes a casing which defines an external appearance thereof. A cooking cavity and a machine room are provided in the casing and separated from each other by a partition wall. An internal duct is provided outside of the cooking cavity and of the machine room in the casing to vent the exhaust gas or the smoke, produced from the oven range which is positioned under the wall-mounted type microwave oven, to the atmosphere.
The internal duct extends around lower portions, rear portions, and upper portions of the cooking cavity and the machine room. An air inlet port is formed at a bottom panel of the casing to suck the exhaust gas or the smoke into the casing. An exhaust fan is provided on an upper portion of the casing, and operates to discharge the exhaust gas and the smoke, which are sucked into the casing via the air inlet port and the internal duct, to the atmosphere.
In the wall-mounted type microwave oven, a power cord is installed to pass through the casing, and operates to supply electric power to a power supply unit which is provided in the casing. In this case, the power cord passes through an upper panel which defines a top wall of the casing.
Since a rear wall of the casing is mounted close to a wall of a kitchen and a side wall of the casing is mounted close to a cupboard to store kitchen utensils, the power cord is not mounted to the rear wall or the side wall of the casing but is mounted to the upper panel of the casing. When the power cord is installed to pass through a bottom wall of the casing, the power cord may be thermally deformed due to heat generated by the oven range which is positioned under the microwave oven.
As illustrated in FIGS. 1 and 2, a mounting hole 4 is formed at a predetermined portion of an upper panel 2 which defines a top wall of a casing 1, so that a power cord 3 is installed to pass through the upper panel 2 of the casing 1.
A plug 3a is provided at an end of the power cord 3 which is outside the mounting hole 4, and is connected to an external power source. A locking unit 5 is provided at a predetermined portion of the power cord 3 to lock the power cord 3 to the upper panel 2.
The locking unit 5 is provided around a circumferential surface thereof with a locking groove 5a, thus engaging with the mounting hole 4 at the locking groove 5a. The mounting hole 4 is provided with a locking notch 4a, so that the locking groove 5a of the locking unit 5 engages with an edge of the locking notch 4a. 
Further, the mounting hole 4 is provided with a guide opening 4b. The guide opening 4b has a width larger than the locking unit 5 to easily guide the locking unit 5 into the locking notch 4a. That is, the locking unit 5 engages with the edge of the locking notch 4a through the guide opening 4b of the mounting hole 4.
When the locking unit 5 engages with the edge of the locking notch 4a, the guide opening 4b is open. Thus, contaminants, such as dust, may flow into the casing 1 through the open guide opening 4b. 
To prevent the contaminants, such as dust, from flowing into the casing 1 through the mounting hole 4 and to engage the locking unit 5 to the mounting hole 4, a cover 6 is mounted to the mounting hole 4. The cover 6 is fastened to the upper panel 2 using a fastener, such as a setscrew, thus covering the mounting hole 4. A stopper 6a is provided at an end of the cover 6 to surround a part of an upper surface and a side surface of the locking units, thus preventing the locking unit 5 from being unexpectedly removed from the locking notch 4a. 
However, the conventional wall-mounted type microwave oven has a problem that components, such as a cover, are additionally required, so a manufacturing cost is increased, The conventional wall-mounted type microwave oven has another problem that the cover is fastened to a casing using a setscrew, so its assembling efficiency is poor.
Accordingly, it is an aspect of the present invention to provide a wall-mounted type microwave oven which reduces a number of required components, thus reducing a manufacturing cost of the wall-mounted type microwave oven, and enhancing an assembling efficiency of the wall-mounted type microwave oven.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The above and/or other aspects of the present invention are achieved by providing a wall-mounted type microwave oven, including a casing defining an external appearance of the wall-mounted type microwave oven, a power cord passing through an upper panel, which defines a top wall of the casing to supply external electrical power into the casing, and a mounting hole formed at the upper panel of the casing so as to be opened at a rear end of the upper panel, thus allowing the power cord to pass through the upper panel. The wall-mounted type microwave oven also includes a locking unit provided at a predetermined portion of the power cord to engage with the mounting hole, thus locking the power cord to the upper panel, and a rear panel defining a rear wall of the casing and supporting a rear end of the locking unit.
The locking unit is provided around a circumferential surface thereof with a locking groove, thus engaging with the mounting hole at a locking groove. The mounting hole includes a locking notch having a width corresponding to the locking groove so that the locking groove of the locking unit engages with an edge of the locking notch, and a guide opening having a width larger than the locking unit to guide the locking unit into the locking notch.
Further, a support rib forwardly extends along an upper edge of the rear panel to support the rear end of the locking unit and close the guide opening.
The locking unit includes upper and lower bodies of a rectangular plate shaped so as to define the locking groove between the upper and lower bodies.
The upper panel is depressed downwardly at a portion around the locking notch, thus preventing the upper body of the locking unit from being projected from the upper panel of the casing.
Further, the locking unit is integrated with the power cord.